Regulating transformer



March 14, 1939. G, LElSCHNER REGULATING TRANSFORMER 4 Sheets-Sheet 1Filed June 11, 1937 I JNVENTOR GEORG' LE/SCHNER kiqw ATTORNEYS'REGULATING, TRANSFORMER 4 Sheets-Sheet 2 Filed June 11, 1937 Lil 'INVENTOR CEORG LEIS'Cl/MER March 14, 1939. v v G. LEISCHNER 2,150,382

I REGULATING TRANSFORMER I Filed June 11, 1937 4 Sheets-Sheet 5 Fig.3

37w T Q L. f

, I f I 1 INVIENTOR 31! 1s EORG LEISfHNER ATTORN E V5 March 14, 1939.

LEISCHNER REGU .JTING TRANSFORMER -4 Sheets-Sheet 4 Filed June 11, 1957mvENToR G EORE LEISCHNE Patented Mar. 14, 1939 UNITED STATES 2,150,382BEGULATING 'rnaivsromvme Georg Lcischner,

Berlin- Schmockwitz, Germany,

.assignor to Julius Pintsch Kommanditgesellschaft, Berlin, GermanyApplication June 11, 1937, Serial No. 147,77

In Germany June 11, 1936 16 Claims.

The invention relates to a regulating transformer for the practicallystepless regulation of potential with a set of brushes rotatable aboutthe core of the transformer or with a rotatable winding.

In the 'case of the known transformers of this kind, the potential isvaried substantially by a jump of an entire turn potential at eachcomplete revolution of the brushes about the core. In order to avoidthis potential jump and to produce an at least approximately continuousregulation of, potential there has therefore already been provided incombination with the rotatable brushes a potential divider from whichthe regulated potential can be taken off.

The subject-matter or the invention is a regulating transformer by meansof which there can be obtained an increase of the regulated potentialthat is approximately continuous or as finely graduated as desiredwithout its being necessary to provide special potential dividers.According to the invention the iron core of this transformer is divided,and the regulating winding is applied to the core and, if required,provided with tappings led through between the limbs, for the time beingtraversed by a part of the exciting flux, so

that on the shifting of the regulating brush along the winding thepotential is varied by an amount which corresponds to only a fraction ofthe entire exciting flux and which may be made as small as desired and,consequently, only a fraction of the complete turn potential.

Specially advantageous is the construction of the transformer as ashell-type transformer the shell of which is divided into severalseparate return paths. The tappings of the regulating windingsurrounding the main limb are then advantageously led outwards betweenthese return paths and there formed as a spiral contact path whichextends parallel to the regulating winding and along which then slidesthebrush, which is preferably rotatable about the transformer. In thisway the transformer is given an extremely compact and closed form, whichis particularly advantageous also as regards leakage losses.

In 'a particularly preferred constructional example of the invention theseveral regulating turns with tappings are constructed in the form ofannular and slit metal sheets. Each metal sheet is connected at the slitwith the succeeding metal sheet in such a manner that there results ahelical turn arranged around the main core.

Some constructional examples of the invention are shown inthe drawings,in which,.Figure 1 is a, vertical section through one form ofconstruction embodying my invention; Figure 1b is a horizontal sectionthrough the construction shown in Figure 1; Figures 2, 3 and 4 areelevations, partly in section, and Figures 21), 3b and 4b horizontalsections, respectively, showing three 5 other embodiments of theinvention, and Figure 5 is a diagrammatic illustration of a three-phasetransformer system constructed in accordance with the invention.

In Figure l, i denotes the core of the regulating transformer, which isin this case surrounded by twelve return paths 3. .The laminated core Ihas the form of a hollow cylinder and is composed of separate (twelve)segments (Figure 1b). The connection with the return paths, which are'likewise laminated in the direction of the radius, is efiected by meansof yoke plates 2, which may if required also be laminated. .The yokeplates serve at the same time for-holding together the entire iron coreand are pressed together by means of a spindle 8.

The exciting winding 5 surrounds the core I and is in its turnsurrounded by the secondary winding (regulating winding). The latterconsists of metal discs 4, which are slit at 4" and are in each casethere electrically well connected with the succeeding sheet by welding(preferably by butt welding) or soldering or some other method. Thesheets themselves are provided with tappings 6, which widen outwards andeach two of which enclose one of the return paths 3. The annular sheetmetal discs i with the tappings are advantageously stamped out of oneandthe same sheet, preferably copper or brass sheet, in a singleoperation.

The bolts 6 and the spacing pieces I serve for supporting and holdingthe several annular sheets, which extend collectively helically aroundthe core. Between the several turns there isa comparatively largeinterspace through which the 40 air can pass so that a good cooling ofthe transformer is ensured.

The widenings of the several tappings 4 located outside the core systemproduce a practically uninterrupted contact path which extends aroundthe shell-type transformer spirally and along which travels the brush 9,which is preferably formed as a roller.

The primary windin 5 is, in the case of the constructional formaccording to Figure 1, divided into separate coils connected inparallelism (Fig ure 1a) in order to avoid too great leakage with thewinding only partly switched in. This'arrangement is speciallyadvantageous in the case of transformers with comparatively long cores.

The coils are advantageously arranged in such a manner that there isalways a primary coil in the immediate neighbourhood of a switching turnponent transformers the primary windings of which are all connectedtogether in parallel and are consequently mutually independent; of thecondition of loading of the secondary circuit.

The division of the primary cylindrical winding into separate disc coilsis advantageous not only for the purpose of reducing the leakage to a,minimum but also when it is a question of fixing the leakage to anydesired value in accordance with the given conditions. This is essentialparticularly for welding transformers and also for variable chokingcoils. In vantages attach to connecting all the coil ends of the primarywinding to one terminal board or to a suitable switch for the purpose ofconnecting the coils of the primary winding according to requirementsalternatively in groups, in series or in parallel.

The transformer constructed according to the invention is exceedinglysafe as regards shortcircuiting, and individual tappings can beshortcircuited without difficulty during the regulating operation. Inthe case of the arrangement represented in Figure 1b each contact 4corresponds to the twelfth part of the turn potential. In that case,where, as shown in the drawings the roller is just passing from onetapping to the other, a short-circuit current must oc'cur. Now thiscurrent is itself very small; because it can be produced only by atwelfth part of the turn potential, and it is moreover further reducedowing to the fact that the flux' produced by it compensates the excitinghut in the surrounding component limb and deflects it into the othercomponent limbs. In the case of the subject-matter of the invention theflux deflection, owing to suitaround the transformer again a symmetricalloading of the component cores.

It is advantageous to make the flux deflection potential. When in thiscase the current-collecting brush-l bridges the gap Ill directly, thehalf turn-potential in the short circuit surrounding one of thecomponent return paths 3 prodime: a current. As, however, thecorresponding this case special addependent potential drop at the limb 3is blocked as regards the exciting flux by the short circuit, the shortcircuit current cannot be of an undue magnitude. In some circumstancesit may then beadvantageous to make the .roller 9 of resistance materialfor the purpose of limiting the short-circuit current. This isparticularly advantageous when deflection of the flux from one of thereturn paths into the other is to be opposed by a. resistance and theshort circuit current must consequently be reduced in another way.

Also in the case of the arrangement according to Figure 2, aloading-dependent potential drop at the ends of the regulating windingdoes not occur injuriously, because the loading of the component limbsand consequently the distribution of .the exciting flux are alwaysuniform after a complete revolution of the brush.

The transformer constructed according to the invention presents greatadvantage when flux defiection is rendered possible inasmuch as specialload switches need not be provided in this case, and on the contrary,the current-collecting brush can regulate the load circuit directly.

The regulating operation itself takes place, in s the case of theconstructional example here represented, by rotating the entiretransformer on the base-plate M, for example, by means of a forceapplied to the axle i3. Through the toothed ring II and the toothedwheels 12 the rotary mo- 8 tion is transmitted to the roller brush 9,which thereupon, moving axially, rolls on the tappings of the secondarywinding 4. It is particularhr advantageous to arrange for thetransformer to be fixed as a whole and the brush, for example,lows-likesupport and former cores and thus shifted axially. As a guidingdevice forthe brush there may serve the correspondingly formedregulating winding or its taDpings.

A similar construction, likewise in auto-transformer connection, isshown in Figure 3. The turn potential is in this case divided into eightsteps, and the core I has eight return paths 8. The core itself iscomposed of sheet-metal bunbeing fastened to a galdles stepped inrelation to one another, and has essentially the form of a cross. Theseveral return paths are arranged circularly about the core and haverespective yokes 2, with-which they are extended over the core I (Figure3). sheets of the return paths I have rectangular projections formingthe yokes 2. When the transformer is constructed as two-windingtransformers, there may be arranged around the core a special primarywinding in a manner similar to that of Figure 1. The annular metalsheets I put together to form a spiral are here, as is shown 'in Figure3a, placed substantially edgewise. The tappings 4', and may be'also alarger or smaller annular edge of the sheets, extend substantiallyhorizontally and at right angles to the parts of the sheets that areplaced edgewise. This arrangement has the .advantage that thedistribution of the winding within the transformer is facilitated andthat, moreover, the ac tion of the skin effect can be suppressed in afavourable manner.

In order, in the case of this arrangement, when the several fluxconductors are ununiformly loaded, to prevent an undue increase of theloadregulating winding, it may be advantageous to arrange equalizingwindings on the return paths which offer a resistance to a deflection ofthe exciting flux from the 5 the brush 9 only to move, 84

moved around the transsented in Figure 4.

shifted as desired.

"separate yokes 2 there loaded component limbs to the unloaded ones. Itmay be specially advantageous, particularly in the case of transformersfor larger power, to apply the equalizing windings in such a manner thatwhilst a shifting of flux is possible within separate groups of at leasttwo component limbs, flux deflection from these groups to the others issuppressed.

In Figure 3b the arrangement of equalizing windings is represented quitediagrammatically.. For the sake of clearness the several coils l5 areshown only on four return paths (in Figure 3 they are omittedaltogether). Each two of the equalizing coils iii are connected inseries but these groups of coils are all connected in parallel. Theequalizing windings have the effect that the exciting flux must bedistributed uniformly over all the groups (each of two component limbs).v Within the groups the flux may, however, be/

For example, in the case of the position shown of the roller brush 9,the flux is deflected from the return path 3' to the return path 3". Theshort-circuit current flowing around this limb 3' is consequentlylimited. Conversely, when the tappings on the return path 3" areshort-circuited by the roller brush 9 the flux is deflected from thisreturn path to the return path 3. A corresponding statement applies whenthe roller brush short-circuits the tappings on the other return paths.In the case of a short circuit, consequently, a flux deflection isalways possible. On the otherhand, in the case of ununiform loading ofthe regulating transformer, the load current will be able to deflect theexciting flux in each case at most out of one of the return paths 3, sothat an injurious rise of the load-dependent potential drop atthe endsof the regulating winding does not occur.

Both the position and also the number of the turns of the equalizingwindings is a suitable means for enabling the magnitude of the fluxdeflection to be adjusted. For example, the equalizing windings on theyokes 2, will impede the flux shifting less than when the windings arearranged on the return paths 3.

When the turn potential is divided so finely that inthe case of theshort-circuiting of separate tappings injurious currents can no longeroccur, the possibility of flux deflection may in some circumstances beentirely dispensed with. The transformers of this kind frequentlypresent special advantages because in this case there results anabsolutely linearly rising and approximately perfectly continuousregulating-potential curve. A constructional example (if this kind isrepre- The main core I has in this case 24 return paths 3, and the turnpotential is consequently divided into 24 steps. Each return path 3 hasits own yoke 2. The yokes and the return paths are advantageouslystamped out of one and the same metal sheet. Instead; of the may in somecases be used of circular-disc form.

The laminated core I is formed as .a hollow cylinder and the metalsheets are advantageously put together in involute form (Figure 4b). Theregulating winding "4 is arranged around the core. The primary winding 5is again divided into disc coils which are connected in parallel and ofwhich each is located between the metal sheets 4 (Figure 4a). There thusresults a particularly compact construction of the transformer. Ifrequired in this case also equalizing windings maybe arranged on thereturn paths or on their yokes, and indeed all the coils of this windingare then adconnected yoke plates vantageously connected in parallel sothat a deflection of the exciting flux from one return path to the otheris practically altogether impossible.

The guiding of the roller brush 9 is effected by means of two arms I6,which are mounted on the central axle l3 of the transformer and areinsulated in relation thereto. In smaller constructions of thetransformer one of the arms may in some cases be omitted. It may beadvantageous to use two current-collecting brushes and to shift them inopposite directions from the middle of the regulating winding. In thecase of transformers in which the primary winding is formed as acylindrical winding (of coils not connected in parallel), and also inthe case of autotransformers, there then results the advantage that theleakage of the transformer is considerably reduced.

The regulating transformer constructed according to the invention, has,further, special advantages as a three-phase current transformer as isquite diagrammatically shown in Figure 5. In that case each part 20corresponds to a transformer core according to Figures 1-4 for eachphase of @the three-phase current. The star point of the three-phasecurrent transformer is formed by the contact rollers IS. The potentialregulation is effected by rotating the transformercores 20 in thedirection of the arrows or in the opposite direction). For the supply ofcurrentther'e is necessary only one conductor for each of thetransformer cores 20. The conductors are connected through slip rings.Conductors to the contact rollers l9 moving along the winding axis maybe dispensed with. There thus results a particularly advantageous andsimple construction of the arrangement. i

What I claim is:-

1. A regulating transformer having an iron core with a main limb andseveral magnetic return paths connected with the main limb and arrangedin spaced relation around the main limb, a regulating windingsurrounding the main limb and a current-collecting brush, the regulatingwinding being provided with tappings, the tappings extending between thereturn paths to the periphcry of the transformer and there forming ahelical contact-path which extends parallel to the turns of theregulating winding, and means mounting said brush in contact with saidhelical contact-path and permitting relative movement between the same.

2. A regulating transformer as recited in claim 1, in which means areprovided for moving the current-collecting brush along said helicalcontact-path around the fixed transformer core.

3. A regulating transformer as recited in claim 1, in which the ironcore is rotatable and the current-collecting brush comprises acontactroller movably mounted on a stationary rod, said brush beingresponsive to rotation of the iron core to slide along the contact pathand to move in the longitudinal direction of the winding.

4. A regulating transformer having an iron core with a main limb andseveral magnetic return paths connected with the main limb andcircularly disposed in spaced relation around the main limb, aregulating winding surrounding the main limb and having tappings whichextend between the returnpaths to the periphery of the transformer andform a helical contact path extending parallel to the turns of theregulating winding,a current collector, and means mounting said currentcollector for sliding movement along said contact path, the currentcollector being constantly in contact with said contact path sothatduring its movement, before leaving one contact of the contact path,it has already reached the succeeding contact. V

5. A regulating transformer having an iron path.

6. A regulating transformer according to claim 5, in which round areturn-path, the current-collecting brush being so dimensioned thatduring its movement, before leaving one segment, it has already reachedthe next.

8. A regulating transformer-includingan iron core with a main limb and9. A regulating transformer having an iron core with a main limb andseveral magnetic reconnected with the main limb and disposed in spacedrelation about the and there form with their edges a spiral contactpath, and means mounting said current-collector for movement in contactwith said spiral path. v

10. A regulating transformer comprising an iron core with a main limband several magnetic return paths arranged inspaced having a mainrelation around the main limb, an exciting winding, winding, and acurrent collector,

a regulating the exciting tact path which extends parallel to the turnsof the regulating winding, and means mounting said current collector formovement in contact with said spiral contact path.

11. A regulating transformer comprising an iron core with a main" limband several magnetic return paths circularly disposed in spaced relationspiral contact-path which extends parallel to the turns of theregulating winding, and means mounting said current-collector formovement in contact with said spiral contact path.

14. A regulating transformer having an iron core, composed main limb andseveral magnetic return paths circularly disposed in spaced relationaround the main limb, the main limb being formed tubularly form ahelical contact path which extends parallel to the turns of theregulating winding and along which may slide a current-collector.

'15. A three-phase regulating transformer comprising three single-phasetransformers, each single-phase transformer comprising an iron core limband several magnetic return paths arranged in spaced relation around thesaid three single-phase transformers for rotation about their respectiveaxes, three current-collecta spiral conof laminated sheets, including aarouses 5 ins brushes in the form of contact rollers each of which islocated between two of the singlephase transformers and in contact withthe said contact paths of these two transformers simultaneously, andmeans mounting the contact rollers for movement in the axial directionat the windings, the contact rollers forming together the star point ofthe three-phase transformer.

16. A regulating transformer as recited in claim CERTIFICATE OFCORRECTION.

A Patent no. 2,150,582.

GEORG IJEISCHNER.

March n, 19 9.

GEORG LEISCHNER- It is hereby certified that error appears in theprinted specification of the above numbered patent requiring correct ionas follows: Page i first column, line 72, claim9, after the word"spiral" insert contact; same page, second column, line 30, claimlZ, for"coils" read turns; and that the said Letters Patent should be read withthis correction therein that the same may conform to the record of thecase in the Patent Office,

Signed and sealed this 15th day of August, A. D, 1959.

(Seal) Leslie Erazer Acting Commissioner of Patents.

